The present invention relates to excavator bucket linkages.
It is a common practice to pivotally mount an excavator bucket at the end of a dipper stick and to power-rotate the bucket between extreme roll-back and curled positions by means of an extensible and retractable hydraulic actuator operatively connected to the bucket by a linkage comprising a pair of links having respective first ends pivotally joined to each other and the actuator and respective second ends respectively pivotally connected to the dipper stick and the bucket.
The geometry of these conventional bucket linkages is such that the force developed at the bucket cutting edge, as the bucket is rotated from an extreme roll-back to an extreme curled position, begins at some initial value and increases rapidly to a maximum and then drops rather quickly.